Single-acting reciprocating engine



Jan. 18, 1944. J. OLSSON ETAL SINGLE ACTING RECIPROCATING ENGINE Filed Jan. 31 1942 2 Sheets-Sheet 1 Fla. 2

Jan. 18, 1944. V OLSSON A 2,339,510

SINGLE ACTING RECIPROCATING ENGINE Filed Jan. 31, 1942 2 Sheets-Sheet 2.

FIG.- 3

Patented Jan. 18, 1944 SINGLE-ACTING RECIPROUATING ENGINE Johannes Olsson and John Richard Stalblad, Goteborg, Sweden, assignors to Aktiebolaget Giitaverken, Goteborg, Sweden, a corporation of Sweden Application January 31, 1942, Serial No. 429,121 In Sweden April 23, 1941 8 Claims.

The present invention relates to improvements in single acting reciprocating engines, particularly internal combustion engines having piston controlled inlet ports and a pressure chamber at the outside of said inlet ports. Although the invention is particularly applicable on internal combustion engines it should be understood that it may be employed in other reciprocating engines, in which a pressure chamber is disposed outside piston controlled inlet ports of an engine cylinder. In connection with internal combustion engines the invention may be employed in two stroke, four stroke or multiple stroke engines having single acting working pistons and piston controlled inlet ports. The engines may naturally be of any known type such as common trunk or cros head engines, engines with opposed motion pistons or free piston engines or the like.

One object of the invention is to prevent the medium in the pressure chamber from flowing through the inlet ports when they are uncovered by the piston at a side of the piston opposite the working cylinder.

With this and other objects in mind we provide a shut-off means so as to prevent flow through the inlet ports when said ports are uncovered by the piston at the side of the piston opposite the working cylinder.

One advantage of this arrangement is that the length of the piston may be materially reduced relatively to the usual piston length of reciprocating engines of this type. Consequently, the length of the cylinder may be reduced correspondingly. In single acting internal combustion engines the side of the piston opposite the working cylinder may conveniently be used for scavenging and charging air compression.

In the accompanying drawings three embodiments of the invention are illustrated by Way of example.

Fig. 1 is a vertical cross sectional view of a two stroke single acting internal combustion engine according to the invention.

Fig. 2 is a vertical longitudinal section through a cylinder of the internal combustion engine according to Fig. 1.

Fig. 3 is a vertical longitudinal section through the cylinder of the engine according to Figs. 1 and 2 on a larger scale.

Figs. 4 and 5 illustrate cylinders of two further engines according to the invention partially in section.

The two stroke single acting internal combustion engine illustrated in Figs. 1-3 may have any number of cylinders, one of which only is illustrated in the drawings. The engine is provided with a lower frame I, an intermediate frame 2 and a cylinder casing3 disposed on top of the intermediate frame. A crank shaft 4 is mounted in bearings 5 in the bearing frame I and connected by means of a connecting rod 6 and a piston rod I with a relatively short piston 8 movable in a cylinder 9. The cylinder 9 extends into the cylinder casing 3, which is provided with valves I0 disposed in the bottom II of said casing and forming a communication between a compression chamber I2 at the under side of the piston 8 and a scavenging air chamber I3 formed by the cylinder casing 3. The compression chamber I2 is separated from the crank case I, 2 of the engine by a wall I4, through which the piston rod I extends. A packing I5 forms a seal around the piston rod I at the passage through the wall I4. The compression chamber I2 is provided with automatic. inlet valves for fresh air at I6. A valve seat I! and an outlet valve I8 are provided at the top of the cylinder, said valve being through a cross bar I 9 and rods 20 controlled by suitable controlling means such as a cam 2| provided on the crank shaft 4 of the engine and cooperating with a pivotally mounted double armed lever 22 connected with the rod 2.). The rods 20 may naturally be actuated in any other way, for instance by cam or crank mechanisms provided on a separate shaft and the valve may also be of any well known construction, for instance such as a piston valve in an engine with opposed motion pistons. The cylinder 9 is provided with inlet ports 23 uncovered by the piston in the bottom piston position, then admitting scavenging and charging air into the working cylinder through the ports from the scavenging air chamber I3. The working piston 8 is so short that the inlet ports 23 are uncovered by the working piston at the under side of said piston, when the piston is in upper positions in the working cylinder 9. In order to prevent compressed air in the scavenging air chamber I3 from flowing through the ports 23 intothe compression chamber I2 at the under side of the piston shut-off means such as a sleeve valve 24 in Figs. 1. and 2 or 240, in Fig. 3 is displaceable in the axial direction of the cylinder so that the scavenging ports 23 may be covered and uncovered thereby, The sleeve valve 24 is secured between, nuts 26 and abutments 21 on the rods 20 of the valve I8 and consequently the sleeve valve follows the motion of said valve. The sleeve valve 24 in Figs. 1 and 2 is illustrated as a plane valve. In order to reduce the stroke of the sleeve valve said valve may be carried out as a D-sleeve valve as illustrated in the modification 24a in Fig. 3. In this case the sleeve valve is provided with an upper and a lower inlet edge 28 and 29, respectively, between which edges a hollow space 30 is formed in the valve. An external gliding surface 3| on the cylinder has recesses 32 provided therein and in the open position of the valve illustrated in Fig. 3 scavenging and charging air may flow into the cylinder through the ports 23 over the inlet edge 28 directly from the scavenging air chamber l3 and below the inlet edge 29 from the scavenging air chamber l3 through the recesses 32 and-the hollow space 30. Since in the illustrated embodiment the .sleeve valve i connected to the outlet valve motion rods 26 the sleeve valve follows the motion of the valve l8 and is consequently open as long as the valve I8 is open but remains in closed, position when the valve i8 is closed. In the illustrated embodiments the valve I8 is the exhaust valve of the internal combustion engine and the sleeve valve 24 keeps the ports 23 closed during the whole piston motion except the exhaust and charging periods. Since the sleeve valve is directly connected with the control rods of the exhaust valve IS the stroke of the sleeve valve is the same as the stroke of the exhaust valve. Consequently, as soon as the height of the inlet port exceeds the stroke of the outlet valve the sleeve valve has to be arranged in such a manner that the inlet ports are completely covered and completely opened, respectively, upon displacement of said valve, which may for instance be obtained by forming and arranging the sleeve valve as a D-sleeve valve as illustrated at 240. in Fig. 3.

A further embodiment of the invention is illustrated in Fig. 4 which shows the cylinder of a two stroke internal combustion engine. In this figure the same reference numerals as in Figs. 1-3 indicate similar parts. The most important difierence is that in the embodiment illustrated in Fig. 4 the valve motion comprises a separate cam shaft 33 which may be driven from the crank shaft of the engine in any known manner. The inlet ports 23 of the cylinder are provided in the cylinder wall, which forms a part of an annular conduit 34 communicating with the scavenging air chamber I3 through an opening controlled by a poppet valve 35, which is controlled by a spring 35 and a cam 31 on the cam shaft 33. Another cam 38 on said cam shaft actuates the valve gear 39 of the outlet valve All provided in the valve seat 11 at the top of the cylinder. It is obvious that in the embodimen-t illustrated in Fig. 4 the valve 35 must not necessarily make the same movement as the valve 40 and may, for instance, open to full extent before the valve 4!] starts to open so that the valve 40 makes as little resistance as poss'ible to the admission of scavenging and charging air.

In the embodiment illustrated in Fig. 5, which shows the cylinder of an internal combustion engine, the parts which correspond to similar parts in Figs. 1-3 have been indicated by the same reference numerals. In this case the shutoff means for the inlet ports 43 of the cylinder 9 comprises a sleeve valve formed as a ring 4| provided with a number of openings 42 corresponding to the inlet ports 43 of the cylinder and rotatable relatively to the cylinder axis such a distance that said ports are uncovered by the sleeve when the inlet ports 43 register with the sleeve ports 42 and covered by the intermediate Bil portions 44 of the sleeve when the sleeve is turned so that the openings 42 are out of register with the inlet ports 43. For this purpose a crank 45 on a crank shaft 46, which by means of cams 4'! actuates the valve gear 48 of the outlet valve 49 of the cylinder 9, is connected with the sleeve 4| by means of a connecting rod 50. The sleeve 4| may naturally be rotated along a screw line or in any other suitable way.

The embodiments of the invention above described and illustrated in the drawings should only be considered as examples and the invention may be modified in several different ways within the scope of the claims.

What we claim is:

1. In a single acting reciprocating engine, a combustion cylinder, inlet ports in said combustion cylinder, a reciprocating piston in the combustion cylinder controlling the admission through said inlet ports into the combustion cylinder and uncovering said inlet ports during a portion of the piston motion at the side of said piston opposite the combustion cylinder, the length of said piston being shorter than the stroke thereof, a pressure chamber outside the inlet ports, a compression chamber at the rear side of said piston, and shut-ofif means arranged to prevent flow through the inlet ports when said ports are uncovered by the piston at the side of the piston opposite the combustion cylinder.

2. In a single acting reciprocating engine, a working cylinder,-in1et ports in said Working cylinder, a reciprocating piston in the working cylinder controlling the admission through said inlet ports into the Working cylinder and uncovering said inlet ports during a portion of the piston motion at the side of said piston opposite the working cylinder, a pressure chamber outside the inlet ports, a D-sleeve valve with double inlet edges movable at the outside of the cylinder and arranged to prevent flow through the inlet ports when said ports are uncovered by the piston at the side of the piston opposite the working cylinder, and recesses in the cylinder wall at the outside of the cylinder forming a communication between said pressure chamber and the interior of said D-sleeve valve and the inlet ports, when the D-sleeve valve is in open position.

3. In a single acting reciprocating engine, a working cylinder, inlet ports in said working cylinder, a reciprocating piston in the working cylinder controlling the admission through said inlet ports into the working cylinder and uncovering said inlet ports during a portion of the piston motion at the side of said piston opposite the working cylinder, an outlet opening in the working cyilnder, a means for controlling said outlet opening, a mechanism for moving said controlling means in timed relation to the motion of the piston, a pressure chamber outside the inlet. ports, and shut-off means connected with and moved by said mechanism and arranged to prevent flow through the inlet ports, when said ports are uncovered by the piston at the side of the piston opposite the working cylinder.

4. In a single acting two stroke internal combustion reciprocating engine, a working cylinder, inlet ports in said working cylinder, a reciprocating piston in the working cylinder controlling the admission through said inlet ports into the working cylinder and uncovering said inlet ports during a portion of the piston motion at the side of said piston opposite the working cylinder, an outlet opening in the top of the working cylinder, a means controlling said outlet opening, a cross bar connected with said means, two rods para1le1 with the cylinder axis and disposed at the outside of the cylinder and connected with said cross bar, a pressure chamber outside the inlet ports, and shut-off means connected with said rods and arranged to prevent flow to the inlet ports when said ports are uncovered by the piston at the side of the piston opposite the working cylinder.

5. In a single acting reciprocating engine, a combustion cylinder, inlet ports in said combustion cylinder, a reciprocating piston in the combustion cylinder controlling the admission through said inlet ports into the combustion cylinder and uncovering said inlet ports during a portion of the piston motion at the side of said piston opposite the combustion cylinder, the length of said piston being shorter than the stroke thereof, a compression chamber separated from the crank case of the reciprocating engine and disposed at the side of the piston opposite the combustion cylinder, and shut-ofi means disposed between said compression chamber and the inlet ports and arranged to prevent flow through the inlet ports, when said ports are uncovered by the piston at the side of the piston opposite the combustion cylinder.

6. In a single acting reciprocating internal combustion engine, a working cylinder, inlet ports in said working cylinder, a reciprocating piston in the working cylinder controlling the admission through said inlet ports into the working cylinder and uncovering said inlet ports during a portion of the piston motion at the side of said piston opposite the working cylinder, the length of said piston being shorter than the stroke thereof, a pressure chamber outside the inlet ports, a compression chamber formed at the sid of the piston opposite the working cylinder, inlet valves in said compression chamber for admitting air into said chamcombustion cylinder, inlet ports in said com- 7 bustion cylinder, a reciprocating piston in the combustion cylinder controlling the admission through said inlet ports into the combustion cylinder and uncovering said inlet ports during a portion of the piston motion at the side of said piston opposite the combustion cylinder, the length of said piston being shorter than the stroke thereof, a pressure chamber communicating with the outside of the inlet ports through a conduit, a compression chamber at the rear side of said piston and a shut-ofi valve in said conduit arranged to prevent flow through the inlet ports when said ports are uncovered by the piston at the side of the piston opposite the combustion cylinder.

8; In a single acting reciprocating engine, a

combustion cylinder, inlet ports in said combustion cylinder, a reciprocating piston in the combustion cylinder, the length of said piston being shorter than the stroke thereof, said piston controlling the admission of'air through said inlet ports into the combustion cylinder and'uncovering said inlet ports when the piston is in its upper and lower positions, a pressure chamber outside the inlet ports, a compression chamber below said piston, and shut-0E means arranged to prevent flow through the inlet ports into the combustion chamber when said ports are uncovered by the piston in its upper position.

JOHANNES OLSSON.

JOHN RICHARD STALBLAD. 

